1. Field of the Invention
The present invention relates generally to cooling systems, and more particularly to a cooling system capable of defrosting, and the cooling system may provide a working fluid with temperature below 0° C.
2. Description of the Related Art
Upon testing electronic elements or electronic devices composed of electronic elements, such as wafers, integrated circuits, printed circuits, and so on, it is often important to obtain endurable temperatures of a device under test (hereinafter referred to as the “DUT”). This means the DUT has to be tested at various temperatures throughout a specific temperature range. Therefore, a temperature control system is necessary in the aforesaid testing process to control the temperature of the DUT as accurately as possible.
In a conventional temperature control system, a working fluid flowing in a pipe is cooled down by a cooling device and then directed to the surrounding of a DUT so as to cool down the DUT.
However, when the working fluid is very cold, it may frost over the inner wall of the pipe. The thickness of the frost will influence the flow rate of the working fluid. The pipe may be even blocked up by the frost, so that the temperature control system is incapable of regular operation. In such circumstance, the pipe needs to be defrosted, and the conventional way of defrosting the pipe is to shut down the temperature control system and wait for the working fluid to warm up in the ambient temperature to the temperature above 0° C., so that the frosted section in the pipe will be defrosted gradually. However, such way of defrosting is time-consuming. Alternatively, the working fluid can be warmed up quickly by a heater for raising the efficiency of defrosting. However, such way of defrosting costs relatively higher and causes energy consumption.